[net/dns] Only record HaveDnsChanged if the nameserver is not INADDR_ANY.

net/base/host_resolver_impl.cc

Index: net/base/host_resolver_impl.cc
diff --git a/net/base/host_resolver_impl.cc b/net/base/host_resolver_impl.cc
index a66f950e5fa8d9d6c477ebc49e1aaac329df6f6d..1458e3ad7db451241ab78a8594eca3dd98fd6da9 100644
--- a/net/base/host_resolver_impl.cc
+++ b/net/base/host_resolver_impl.cc
@@ -1433,9 +1433,8 @@ class HostResolverImpl::Job : public PrioritizedDispatcher::Job {
       SetPortOnAddressList(requests_->front()->info().port(), &list);
       // Record this histogram here, when we know the system has a valid DNS
       // configuration.
-      UMA_HISTOGRAM_ENUMERATION("AsyncDNS.HaveDnsConfig",
-                                resolver_->received_dns_config_ ? 1 : 0,
-                                2);
+      UMA_HISTOGRAM_BOOLEAN("AsyncDNS.HaveDnsConfig",
+                            resolver_->received_dns_config_);
     }
 
     if ((net_error != ERR_ABORTED) &&
@@ -1966,7 +1965,14 @@ void HostResolverImpl::OnDnsConfigChanged(const DnsConfig& dns_config) {
   }
 
   // TODO(szym): Remove once http://crbug.com/125599 is resolved.
-  received_dns_config_ = dns_config.IsValid();
+  received_dns_config_ = false;
+  if (dns_config.IsValid()) {
+    // Quick check if the address is not INADDR_ANY, which is the default value
+    // in absence of network connection. http://crbug.com/130808
+    if (dns_config.nameservers[0].address()[0]) {

[mmenke, 2012/06/01 22:20:27]

Is it possible that we'd have INADDR_ANY, followed by other addresses?  If not,
LGTM.  If so, might want to check for that.

+      received_dns_config_ = true;
+    }

[mmenke, 2012/06/01 22:20:27]

nit:  No brackets for single-line ifs.

[mmenke, 2012/06/01 22:21:20]

Actually, I'm never sure if that is optional or not...Know it's been discussed
before.  Erm...I really don't care.

[mmenke, 2012/06/01 22:24:14]

Ahh, chromium style guide:

Other formatting "rules" are not required, but are fairly common across Chrome
code, and thus it's probably best to stick to them unless you have a reason not
to.  In particular, if existing code follows these styles, maintain them:
* Prefer (foo == 0) to (0 == foo)
* Omit {} for conditional or loop bodies where the body is just one physical
line.  Otherwise, use {}.
* Function declaration order should match function definition order

+  }
 
   // Life check to bail once |this| is deleted.
   base::WeakPtr<HostResolverImpl> self = AsWeakPtr();